Bottom Line:
Whether the speed of body mass (BM) reduction influences the body composition is uncertain.The skeletal muscle mass did not decrease in R and S.In conclusion, differences of the speed of BM reduction affect the splanchnic tissues, and the decrease in splanchnic tissue mass was greater with rapid than slow BM reduction.

ABSTRACTWhether the speed of body mass (BM) reduction influences the body composition is uncertain. To investigate the effects of rapid vs slow body mass reduction on body composition, rats were divided into three groups; fed ad libitum for 16-day (Control, C); received restricted food intake during 16-day to decrease BM slowly (Slow, S); or fed ad libitum for 13-days and fasted for the last 3 days to rapidly reach a BM comparable to that of S (Rapid, R). Drinking water was restricted for R on day 16 to rapidly decrease their BM. All rats trained during the study. Final BM and adipose tissues mass were similar for R and S, and both were lesser than C. The skeletal muscle mass did not decrease in R and S. The liver mass was lower in R and S than C, and the decrease tended to be greater in R than S. Both the stomach and small intestine masses were significantly lower in R than C, but did not differ between S and C. In conclusion, differences of the speed of BM reduction affect the splanchnic tissues, and the decrease in splanchnic tissue mass was greater with rapid than slow BM reduction.

Mentions:
The design of the study is summarized in Fig. 1. Male Sprague-Dawley rats (5 weeks old, n = 15) were obtained from Japan Clea, Inc. (Tokyo, Japan) and kept individually in metabolic cages. The animal room was maintained at 23°C with a 12-h light-dark cycle (lights on from 2100 to 0900 h). The rats were fed ad libitum a standard rat chow (CE-2, Japan Clea, Inc.) and allowed free access to water for 6 weeks before body mass reduction. All rats were subjected to a climbing exercise. The exercise was accomplished utilizing a wire mesh cage (length 38 × width 28 × height 53 cm) which was placed on a 53°C electric hot plate. This temperature is the minimum temperature to provoke the rats to climb. When the rats were positioned at the bottom of the climbing apparatus during exercise, they were motivated to climb the apparatus by the heating plate. Initially, the rats were familiarized with the wire mesh cage by practicing climbing the apparatus from the bottom to the top cage for 7 days, and then the climbing exercise regimen started. The exercise regimen consisted of 6 times a week (10 min × 3 sets/day) during 6 weeks to mimic the situation in human athletes who engage in routine physical training. Rats were allowed to rest for 10 min between training sessions. All study procedures were conducted in conformity with the Guiding Principles in the Care and Use of Animals.

Mentions:
The design of the study is summarized in Fig. 1. Male Sprague-Dawley rats (5 weeks old, n = 15) were obtained from Japan Clea, Inc. (Tokyo, Japan) and kept individually in metabolic cages. The animal room was maintained at 23°C with a 12-h light-dark cycle (lights on from 2100 to 0900 h). The rats were fed ad libitum a standard rat chow (CE-2, Japan Clea, Inc.) and allowed free access to water for 6 weeks before body mass reduction. All rats were subjected to a climbing exercise. The exercise was accomplished utilizing a wire mesh cage (length 38 × width 28 × height 53 cm) which was placed on a 53°C electric hot plate. This temperature is the minimum temperature to provoke the rats to climb. When the rats were positioned at the bottom of the climbing apparatus during exercise, they were motivated to climb the apparatus by the heating plate. Initially, the rats were familiarized with the wire mesh cage by practicing climbing the apparatus from the bottom to the top cage for 7 days, and then the climbing exercise regimen started. The exercise regimen consisted of 6 times a week (10 min × 3 sets/day) during 6 weeks to mimic the situation in human athletes who engage in routine physical training. Rats were allowed to rest for 10 min between training sessions. All study procedures were conducted in conformity with the Guiding Principles in the Care and Use of Animals.

Bottom Line:
Whether the speed of body mass (BM) reduction influences the body composition is uncertain.The skeletal muscle mass did not decrease in R and S.In conclusion, differences of the speed of BM reduction affect the splanchnic tissues, and the decrease in splanchnic tissue mass was greater with rapid than slow BM reduction.

ABSTRACTWhether the speed of body mass (BM) reduction influences the body composition is uncertain. To investigate the effects of rapid vs slow body mass reduction on body composition, rats were divided into three groups; fed ad libitum for 16-day (Control, C); received restricted food intake during 16-day to decrease BM slowly (Slow, S); or fed ad libitum for 13-days and fasted for the last 3 days to rapidly reach a BM comparable to that of S (Rapid, R). Drinking water was restricted for R on day 16 to rapidly decrease their BM. All rats trained during the study. Final BM and adipose tissues mass were similar for R and S, and both were lesser than C. The skeletal muscle mass did not decrease in R and S. The liver mass was lower in R and S than C, and the decrease tended to be greater in R than S. Both the stomach and small intestine masses were significantly lower in R than C, but did not differ between S and C. In conclusion, differences of the speed of BM reduction affect the splanchnic tissues, and the decrease in splanchnic tissue mass was greater with rapid than slow BM reduction.